@mixin retina {
  $retina-support-respondjs: 0 !default;

  @media (-webkit-min-device-pixel-ratio: 1.5), (min--moz-device-pixel-ratio: 1.5), (-o-min-device-pixel-ratio: 3/2), (min-device-pixel-ratio: 1.5), (min-resolution: 144dppx) {
    // Note: Respond.js does not support pixel-ratio media queries so older browsers (IE8) will apply styles defined within the query.
    // To hide the styles from IE8, add the code within html.mediaqueries
    @if ($retina-support-respondjs == 1) {
      html.mediaqueries & {
        @content;
      }
    }
    @else if $mq-support {
      @content;
    }
  }
}